CN105812056A - Visible light communication method and device aiming at dimming control - Google Patents

Visible light communication method and device aiming at dimming control Download PDF

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Publication number
CN105812056A
CN105812056A CN201610279766.7A CN201610279766A CN105812056A CN 105812056 A CN105812056 A CN 105812056A CN 201610279766 A CN201610279766 A CN 201610279766A CN 105812056 A CN105812056 A CN 105812056A
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signal frame
signal
visible light
minus polarity
threshold
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CN105812056B (en
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杨昉
高俊男
宋健
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Tsinghua University
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Tsinghua University
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Priority to PCT/CN2016/102207 priority patent/WO2017185665A1/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
    • H04B10/114—Indoor or close-range type systems
    • H04B10/116—Visible light communication
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/50—Transmitters
    • H04B10/516—Details of coding or modulation
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]

Abstract

The invention discloses a visible light communication method and device aiming at dimming control. The method comprises the following steps of: modulating a bit to be transmitted to obtain a positive polarity signal frame and a negative polarity signal frame; determining a ratio of the positive polarity signal frame to the negative polarity signal frame as well as a signal frame amplification factor according to a required light modulation degree; multiplying the positive and negative polarity signal frames by the signal frame amplification factor, and mixing according to the ratio to obtain a mixed signal frame; and adding the negative polarity signal frame in the mixed signal frame with DC bias to obtain a signal frame to be transmitted, performing digital to analog conversion on the signal frame to be transmitted, performing frequency conversion and filtration, controlling visible light driving current, and obtaining a visible light communication signal to be transmitted. Through the method, while visible light communication, lighting dimming control can be taken into account, so that on the premise of not affecting a visible light communication condition, large-scale and fine dimming control can be realized, and advantages such as lager communication signal to noise ratio and high energy efficiency are provided.

Description

Visible light communication method and apparatus towards brightness adjustment control
Technical field
The present invention relates to visible light communication and intelligent lighting technical field, particularly to a kind of visible light communication method and apparatus towards brightness adjustment control.
Background technology
VLC (VisibleLightCommunication, visible light communication) it is a kind of technological means realizing radio communication on the basis of LED illumination, utilize light source to send high-frequency signal that naked eyes cannot discover to transmit information, cover with its frequency spectrum width, green energy conservation, the degree of depth, can with the feature that illumination organically combines and have good development prospect.
In visible light communication, except improving except information transmission performance, also it is the technology of an extremely important and great practical value for the brightness adjustment control of VLC system illumination function.Utilize dimming control technique that intensity of light can control within the required range and make full use of the dynamic linear response range of LED so that people can according to oneself to lighting intensity and the requirement adjustment room lighting condition saving energy.Industrial widely used two kinds of dimming control techniques: a kind of is that the continuous current realizing light modulation by reducing forward current regulates (CCR) light regulating technology, and another kind is pulse width modulation (PWM) light regulating technology realizing light modulation by regulating dutycycle.The advantage of CCR is in that simple, stable, and the advantage of PWM is in that to provide wider dimming scope, and can linear regulation light intensity.
But, how while ensureing reliable broadband communication link, to meet high-quality illumination condition visible light communication is particularly important, but the dimming control technique in correlation technique still suffers from some problems, for instance: on the one hand, existing communication mechanism cannot realize brightness adjustment control flexibly；On the other hand, it is achieved its communication energy of the system of brightness adjustment control is inefficient.
Summary of the invention
It is contemplated that one of technical problem solved at least to a certain extent in correlation technique.
For this, it is an object of the present invention to propose a kind of visible light communication method towards brightness adjustment control, the method can take into account illumination brightness adjustment control while visible light communication.
Further object is that a kind of visible light communication device towards brightness adjustment control of proposition.
For reaching above-mentioned purpose, one aspect of the present invention embodiment proposes a kind of visible light communication method towards brightness adjustment control, comprises the following steps: treats transmitted bit and is modulated obtaining positive signal frame and minus polarity signal frame；Proportion and the signal frame amplification factor of described positive signal frame and minus polarity signal frame is determined according to required light modulation degree；Described positive signal frame and minus polarity signal frame are multiplied by described signal frame amplification factor, and carry out mixing to obtain mixed signal frame according to described proportion；By the minus polarity signal frame in described mixed signal frame plus direct current biasing, to obtain signal frame to be sent, after described signal frame to be sent is carried out digital to analog conversion, frequency conversion, filtering, control visible ray drive electric current, and send after obtaining visible light communication signal.
The visible light communication method towards brightness adjustment control of the embodiment of the present invention, illumination brightness adjustment control can be taken into account while visible light communication, when not affecting visible light communication, it is possible to the brightness adjustment control realize on a large scale, become more meticulous, there is the communication advantages such as signal to noise ratio is big, energy efficiency is high.
It addition, the visible light communication method towards brightness adjustment control according to the above embodiment of the present invention can also have following additional technical characteristic:
Alternatively, in one embodiment of the invention, described positive signal is ACO-OFDM signal frame, PAM-DMT signal frame and the one in HACO-OFDM signal frame；Described minus polarity signal frame carries out positive portion zero setting by the bipolar signal before described ACO-OFDM signal frame or described PAM-DMT signal frame or the described asymmetric amplitude limit of HACO-OFDM signal frame and retains described bipolar signal negative fraction and obtain.
Further, in one embodiment of the invention, the maximum current that the value of described direct current biasing is interval less than or equal to visible-light linear.
Further, in one embodiment of the invention, if described required light modulation degree is less than first threshold, only uses described positive signal frame, and reach described required light modulation degree by adjusting described signal amplification factor；If described required light modulation degree is more than Second Threshold, only uses described minus polarity signal frame, and reach described required light modulation degree by adjusting described signal amplification factor；If described required light modulation degree is between described first threshold and Second Threshold, fixing described signal amplification factor, regulate the ratio of described positive signal and minus polarity signal, so that described positive signal frame and the weighted mean of minus polarity signal frame are equal to described required light modulation degree.
Further, in one embodiment of the invention, described first threshold and described Second Threshold are fixed really, reach default value for making time-domain signal cut top ratio, or it is maximum with the ratio cutting top distortion power and noise power sum to make signal power.
For reaching above-mentioned purpose, another aspect of the present invention embodiment proposes a kind of visible light communication device towards brightness adjustment control, including: signal generation module, it is used for treating transmitted bit and is modulated obtaining positive signal frame and minus polarity signal frame；Parameter generation module, for determining proportion and the signal frame amplification factor of described positive signal frame and minus polarity signal frame according to required light modulation degree；Signal fused module, for described positive signal frame and minus polarity signal frame are multiplied by described signal frame amplification factor, and carries out mixing to obtain mixed signal frame according to described proportion；Signal transmitting module, for the minus polarity signal frame in described mixed signal frame is added direct current biasing, to obtain signal frame to be sent, drive electric current described signal frame to be sent carries out controlling after digital to analog conversion, frequency conversion, filtering visible ray, and send after obtaining visible light communication signal.
The visible light communication device towards brightness adjustment control of the embodiment of the present invention, illumination brightness adjustment control can be taken into account while visible light communication, when not affecting visible light communication, it is possible to the brightness adjustment control realize on a large scale, become more meticulous, there is the communication advantages such as signal to noise ratio is big, energy efficiency is high.
It addition, the visible light communication device towards brightness adjustment control according to the above embodiment of the present invention can also have following additional technical characteristic:
Alternatively, in one embodiment of the invention, described positive signal is ACO-OFDM signal frame, PAM-DMT signal frame and the one in HACO-OFDM signal frame；Described minus polarity signal frame carries out positive portion zero setting by the bipolar signal before described ACO-OFDM signal frame or described PAM-DMT signal frame or the described asymmetric amplitude limit of HACO-OFDM signal frame and retains described bipolar signal negative fraction and obtain.
Further, in one embodiment of the invention, the maximum current that the value of described direct current biasing is interval less than or equal to visible-light linear.
Further, in one embodiment of the invention, when described required light modulation degree is less than first threshold, only uses described positive signal frame, and reach described required light modulation degree by adjusting described signal amplification factor；When described required light modulation degree is more than Second Threshold, only uses described minus polarity signal frame, and reach described required light modulation degree by adjusting described signal amplification factor；When described light modulation degree is between described first threshold and Second Threshold, fixing described signal amplification factor, regulate the ratio of described positive signal and minus polarity signal, so that described positive signal frame and the weighted mean of minus polarity signal frame are equal to described required light modulation degree.
Further, in one embodiment of the invention, described first threshold and described Second Threshold are fixed really, reach default value for making time-domain signal cut top ratio, or it is maximum with the ratio cutting top distortion power and noise power sum to make signal power.
Aspect and advantage that the present invention adds will part provide in the following description, and part will become apparent from the description below, or is recognized by the practice of the present invention.
Accompanying drawing explanation
The present invention above-mentioned and/or that add aspect and advantage will be apparent from easy to understand from the following description of the accompanying drawings of embodiments, wherein:
Fig. 1 is according to an embodiment of the invention towards the flow chart of the visible light communication method of brightness adjustment control；
Fig. 2 be according to an embodiment of the invention positive signal frame, minus polarity signal frame and mixed signal frame schematic diagram；
Fig. 3 is according to an embodiment of the invention towards the signal frame schematic diagram to be sent in the visible light communication method of brightness adjustment control；And
Fig. 4 is according to an embodiment of the invention towards the structural representation of the visible light communication device of brightness adjustment control.
Detailed description of the invention
Being described below in detail embodiments of the invention, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has the element of same or like function from start to finish.The embodiment described below with reference to accompanying drawing is illustrative of, it is intended to is used for explaining the present invention, and is not considered as limiting the invention.
Describe the visible light communication method towards brightness adjustment control and device that propose according to embodiments of the present invention with reference to the accompanying drawings, describe the visible light communication method towards brightness adjustment control proposed according to embodiments of the present invention first with reference to the accompanying drawings.
Fig. 1 is the flow chart of the visible light communication method towards brightness adjustment control of one embodiment of the invention.
As it is shown in figure 1, should comprise the following steps towards the visible light communication method of brightness adjustment control:
In step S101, treat transmitted bit and be modulated obtaining positive signal frame and minus polarity signal frame.
It is to say, be first modulated by bit to be transmitted, produce positive signal frame and minus polarity signal frame.Wherein, in one embodiment of the invention, positive signal is the one in ACO-OFDM signal frame, PAM-DMT signal frame and HACO-OFDM signal frame, and namely positive signal frame can be ACO-OFDM signal frame or PAM-DMT signal frame or HACO-OFDM signal frame.
Further, in one embodiment of the invention, minus polarity signal frame carries out positive portion zero setting by the bipolar signal before ACO-OFDM signal frame or PAM-DMT signal frame or the asymmetric amplitude limit of HACO-OFDM signal frame and retains bipolar signal negative fraction and obtain.
In step s 102, proportion and the signal frame amplification factor of positive signal frame and minus polarity signal frame is determined according to required light modulation degree.
Further, in one embodiment of the invention, if required light modulation degree is less than first threshold, only uses positive signal frame, and reach required light modulation degree by adjusting signal amplification factor；If required light modulation degree is more than Second Threshold, only uses minus polarity signal frame, and reach required light modulation degree by adjusting signal amplification factor；If required light modulation degree is between first threshold and Second Threshold, fixed signal amplification factor, regulate the ratio of positive signal and minus polarity signal, so that the weighted mean of positive signal frame and minus polarity signal frame is equal to required light modulation degree.
Wherein, in one embodiment of the invention, first threshold and Second Threshold are fixed really, reach default value for making time-domain signal cut top ratio, or it is maximum with the ratio cutting top distortion power and noise power sum to make signal power.Default value can be configured according to practical situation.
It is to say, when light modulation degree η is less than first threshold η1Time, only use positive signal frame, by adjusting signal amplification factor β, making modulation degree is η；When light modulation degree η is more than Second Threshold η2Time, only use minus polarity signal frame, by adjusting signal amplification factor β, making modulation degree is η；When modulation degree is at first threshold η1With Second Threshold η2Between time, fixed signal amplification factor β, regulating positive signal ratio is α, makes the weighted mean threshold value of positive and negative polarity signal frame equal to η, i.e. η=α η1+(1-α)η2。
It should be noted that first threshold η1With Second Threshold η2Really fix, be: make time-domain signal cut top ratio and reach certain numerical value, it is preferable that cutting top ratio is 1%.Or, first threshold η1With Second Threshold η2Really fix, be: it is maximum with the ratio cutting top distortion power and noise power sum to make signal power.
In step s 103, as in figure 2 it is shown, positive signal frame and minus polarity signal frame are multiplied by signal frame amplification factor, and carry out mixing to obtain mixed signal frame according to proportion.
In step S104, as it is shown on figure 3, by the minus polarity signal frame in mixed signal frame plus direct current biasing, to obtain signal frame to be sent, drive electric current signal frame to be sent carries out controlling after digital to analog conversion, frequency conversion, filtering visible ray, and send after obtaining visible light communication signal.
Further, in one embodiment of the invention, the maximum current that the value of direct current biasing is interval less than or equal to visible-light linear.
With specific embodiment, the visible light communication method towards brightness adjustment control of the embodiment of the present invention is described in detail below.
Embodiment 1
The present embodiment specifically discloses a kind of visible light communication method towards brightness adjustment control, and wherein, signal modulation system is ACO-OFDM modulation, and the method comprises the following steps:
S1: be modulated by bit to be transmitted, produces positive signal frame and minus polarity signal frame.
Specifically, produce positive signal frame, specifically include: bit to be transmitted obtains the constellation mapping symbol X of energy normalized after 16QAM constellation mappingk, after constituting Hermitian symmetrical structure, only in odd subcarriers transmitting data, even subcarriers zero setting, serioparallel exchange carries out inverse fast Fourier transform and obtains time domain bipolar signal x after obtaining the OFDM data block that length is Nn, bipolar signal is carried out asymmetric amplitude limit, with by the negative fraction zero setting of bipolar signal, and retains the positive portion of described bipolar signal, obtain positive signal frame
Further, produce minus polarity signal frame, specifically include: bit to be transmitted obtains the constellation mapping symbol X of energy normalized after 16QAM constellation mappingk, after constituting Hermitian symmetrical structure, only in odd subcarriers transmitting data, even subcarriers zero setting, serioparallel exchange carries out inverse fast Fourier transform and obtains time domain bipolar signal x after obtaining the OFDM data block that length is Nn, bipolar signal is carried out asymmetric amplitude limit, with by the positive portion zero setting of bipolar signal, and retains the negative fraction of described bipolar signal, obtain minus polarity signal frame
S2: determine positive signal frame and minus polarity signal frame proportion and signal frame amplification factor β according to required light modulation degree η.
Wherein, the light modulation degree of LEDWherein ILIt is the linear interval minimum current of LED, IHIt is maximum current, IDIt it is LED work average current.
Further, the signal frame x after energy normalizednMean power be 1, positive signal frameWith minus polarity signal frameRoot-mean-squareSignal frame amplification factor β.
Signal amplitude needs the probability of Clipping to be:
P ( &beta;x n + > I H - I L ) = P ( &beta;x n - < I L - I H ) = P ( x n + > I H - I L &beta; ) = &Integral; ( I H - I L ) / &beta; &infin; 1 2 &pi; exp ( - x n + 2 2 ) d x .
First threshold η1With Second Threshold η2Really fix, be: making time-domain signal cut top ratio is 2.3%, then signal frame amplification factor
First thresholdSecond Threshold
Light modulation degree η=0.1, less than first threshold η1Time, positive signal frame proportion α+=1, minus polarity signal frame proportion α-=0.
Signal frame amplification factor
S3: positive signal frame is multiplied by signal frame amplification factor β, directly obtains mixed signal frame.
S4: after mixed signal frame carries out the operation such as digital to analog conversion, frequency conversion, filtering, controls visible ray and drives electric current, and sends after obtaining visible light communication signal.
Embodiment 2
The present embodiment specifically discloses a kind of visible light communication method towards brightness adjustment control, and wherein, signal modulation system is PAM-DMT modulation, and the method comprises the following steps:
S1: be modulated by bit to be transmitted, produces positive signal frame and minus polarity signal frame.
Specifically, produce positive signal frame, specifically include: bit to be transmitted is modulated according to the modulation system of PAM-DMT, obtains positive signal frame
Further, produce minus polarity signal frame, specifically include: bit to be transmitted is modulated according to the modulation system of PAM-DMT, by the bipolar signal before asymmetric amplitude limit, carry out positive portion zero setting, retain described bipolar signal negative fraction and obtain minus polarity signal frame
S2: determine positive signal frame and minus polarity signal frame proportion and signal frame amplification factor β according to required light modulation degree η.
Wherein, the light modulation degree of LEDWherein ILIt is the linear interval minimum current of LED, IHIt is maximum current, IDIt it is LED work average current.
Further, the signal frame x after energy normalizednMean power be 1, positive signal frameWith minus polarity signal frameRoot-mean-squareSignal frame amplification factor β.
Signal amplitude needs the probability of Clipping to be:
P ( &beta;x n + > I H - I L ) = P ( &beta;x n - < I L - I H ) = P ( x n + > I H - I L &beta; ) = &Integral; ( I H - I L ) / &beta; &infin; 1 2 &pi; exp ( - x n + 2 2 ) d x .
First threshold η1With Second Threshold η2Really fix, be: making time-domain signal cut top ratio is 2.3%, then signal frame amplification factor
First thresholdSecond Threshold
Light modulation degree η=0.5, more than first threshold η1, less than Second Threshold η2Time positive signal frame proportion α+=0.5, minus polarity signal frame proportion α-=0.5.
Signal frame amplification factor
S3: positive signal frame and minus polarity signal frame are multiplied by signal frame amplification factor β, obtains mixed signal frame according to described proportion blended anode signal frame and minus polarity signal frame.
Specifically, positive signal frame and minus polarity signal frame are multiplied by amplification factor β, mix with the ratio that minus polarity signal frame is 1:1 according to positive signal frame, it is preferable that, after each positive signal frame, connect a minus polarity signal frame, obtain mixed signal frame.
S4: by the minus polarity signal frame in mixed signal frame plus direct current biasing IH-IL, obtain signal frame to be sent, then after carrying out the operations such as digital to analog conversion, frequency conversion, filtering, control visible ray and drive electric current, and send after obtaining visible light communication signal.
Embodiment 3
The present embodiment specifically discloses a kind of visible light communication method towards brightness adjustment control, and wherein, signal modulation system is HACO-OFDM modulation, and the method comprises the following steps:
S1: be modulated by bit to be transmitted, produces positive signal frame and minus polarity signal frame.
Specifically, produce positive signal frame, specifically include: bit to be transmitted is modulated according to the modulation system of HACO-OFDM, obtains positive signal frame
Further, produce minus polarity signal frame, specifically include: bit to be transmitted is modulated according to the modulation system of HACO-OFDM, by the bipolar signal before asymmetric amplitude limit, carry out positive portion zero setting, retain described bipolar signal negative fraction and obtain minus polarity signal frame
S2: determine positive signal frame and minus polarity signal frame proportion and signal frame amplification factor β according to required light modulation degree η.
Wherein, the light modulation degree of LEDWherein ILIt is the linear interval minimum current of LED, IHIt is maximum current, IDIt it is LED work average current.
Further, the signal frame x after energy normalizednMean power be 1, positive signal frameWith minus polarity signal frameRoot-mean-squareSignal frame amplification factor β.
First threshold η1With Second Threshold η2Really fix, be: make signal power and cut top distortion power PDistortionWith noise power PnoiseThe ratio of sum is maximum, then signal frame amplification factor
First thresholdSecond Threshold η2=1-η1。
Light modulation degree η is more than Second Threshold η2Time, positive signal frame proportion α+=0, minus polarity signal frame proportion α-=1.
Signal frame amplification factor
S3: minus polarity signal frame is multiplied by signal frame amplification factor β, directly obtains mixed signal frame.
S4: by the minus polarity signal frame in mixed signal frame plus direct current biasing IH-IL, obtain signal frame to be sent, then after carrying out the operations such as digital to analog conversion, frequency conversion, filtering, control visible ray and drive electric current, and send after obtaining visible light communication signal.
The visible light communication method towards brightness adjustment control according to embodiments of the present invention, illumination brightness adjustment control can be taken into account while visible light communication, when not affecting visible light communication, it is possible to the brightness adjustment control realize on a large scale, become more meticulous, there is the communication advantages such as signal to noise ratio is big, energy efficiency is high.
The visible light communication device towards brightness adjustment control proposed according to embodiments of the present invention is described referring next to accompanying drawing.
Fig. 4 is the structural representation of the visible light communication device towards brightness adjustment control of one embodiment of the invention.
As shown in Figure 4, should include towards the visible light communication device 10 of brightness adjustment control: signal generation module 100, parameter generation module 200, signal fused module 300 and signal transmitting module 400.
Wherein, signal generation module 100 is used for treating transmitted bit and is modulated obtaining positive signal frame and minus polarity signal frame.Parameter generation module 200 for determining proportion and the signal frame amplification factor of positive signal frame and minus polarity signal frame according to required light modulation degree.Signal fused module 300 is for being multiplied by signal frame amplification factor by positive signal frame and minus polarity signal frame, and carries out mixing to obtain mixed signal frame according to proportion.Signal transmitting module 400 is for adding direct current biasing by the minus polarity signal frame in mixed signal frame, to obtain signal frame to be sent, drive electric current described signal frame to be sent carries out controlling after digital to analog conversion, frequency conversion, filtering visible ray, and send after obtaining visible light communication signal.The device 10 of the embodiment of the present invention can take into account illumination brightness adjustment control while visible light communication, when not affecting visible light communication, it is possible to the brightness adjustment control realize on a large scale, become more meticulous, and has the communication advantages such as signal to noise ratio is big, energy efficiency is high.
Alternatively, in one embodiment of the invention, positive signal can be ACO-OFDM signal frame, PAM-DMT signal frame and the one in HACO-OFDM signal frame.
Further, in one embodiment of the invention, minus polarity signal frame can carry out positive portion zero setting by the bipolar signal before ACO-OFDM signal frame or PAM-DMT signal frame or the asymmetric amplitude limit of HACO-OFDM signal frame and retain bipolar signal negative fraction and obtain.
Further, in one embodiment of the invention, the maximum current that the value of direct current biasing is interval less than or equal to visible-light linear.
Further, in one embodiment of the invention, when required light modulation degree is less than first threshold, only uses positive signal frame, and reach required light modulation degree by adjusting signal amplification factor；When required light modulation degree is more than Second Threshold, only uses minus polarity signal frame, and reach required light modulation degree by adjusting signal amplification factor；When light modulation degree is between first threshold and Second Threshold, fixed signal amplification factor, regulate the ratio of positive signal and minus polarity signal, so that the weighted mean of positive signal frame and minus polarity signal frame is equal to required light modulation degree.
Wherein, in one embodiment of the invention, first threshold and Second Threshold are fixed really, reach default value for making time-domain signal cut top ratio, and it is maximum with the ratio cutting top distortion power and noise power sum to make signal power.
It should be noted that the aforementioned explanation to the visible light communication embodiment of the method towards brightness adjustment control is also applied for the visible light communication device towards brightness adjustment control of this embodiment, repeat no more herein.
The visible light communication device towards brightness adjustment control according to embodiments of the present invention, illumination brightness adjustment control can be taken into account while visible light communication, when not affecting visible light communication, it is possible to the brightness adjustment control realize on a large scale, become more meticulous, there is the communication advantages such as signal to noise ratio is big, energy efficiency is high.
In describing the invention, it will be appreciated that, term " " center ", " longitudinal direction ", " transverse direction ", " length ", " width ", " thickness ", " on ", D score, " front ", " afterwards ", " left side ", " right side ", " vertically ", " level ", " top ", " end " " interior ", " outward ", " clockwise ", " counterclockwise ", " axially ", " radially ", orientation or the position relationship of the instruction such as " circumference " are based on orientation shown in the drawings or position relationship, it is for only for ease of the description present invention and simplifies description, rather than the device of instruction or hint indication or element must have specific orientation, with specific azimuth configuration and operation, therefore it is not considered as limiting the invention.
Additionally, term " first ", " second " are only for descriptive purposes, and it is not intended that indicate or imply relative importance or the implicit quantity indicating indicated technical characteristic.Thus, define " first ", the feature of " second " can express or implicitly include at least one this feature.In describing the invention, " multiple " are meant that at least two, for instance two, three etc., unless otherwise expressly limited specifically.
In the present invention, unless otherwise clearly defined and limited, the term such as term " installation ", " being connected ", " connection ", " fixing " should be interpreted broadly, for instance, it is possible to it is fixing connection, it is also possible to be removably connect, or integral；Can be mechanically connected, it is also possible to be electrical connection；Can be joined directly together, it is also possible to be indirectly connected to by intermediary, it is possible to be connection or the interaction relationship of two elements of two element internals, unless otherwise clear and definite restriction.For the ordinary skill in the art, it is possible to understand above-mentioned term concrete meaning in the present invention as the case may be.
In the present invention, unless otherwise clearly defined and limited, fisrt feature second feature " on " or D score can be that the first and second features directly contact, or the first and second features are by intermediary mediate contact.And, fisrt feature second feature " on ", " top " and " above " but fisrt feature directly over second feature or oblique upper, or be merely representative of fisrt feature level height higher than second feature.Fisrt feature second feature " under ", " lower section " and " below " can be fisrt feature immediately below second feature or obliquely downward, or be merely representative of fisrt feature level height less than second feature.
In the description of this specification, specific features, structure, material or feature that the description of reference term " embodiment ", " some embodiments ", " example ", " concrete example " or " some examples " etc. means in conjunction with this embodiment or example describe are contained at least one embodiment or the example of the present invention.In this manual, the schematic representation of above-mentioned term is necessarily directed to identical embodiment or example.And, the specific features of description, structure, material or feature can combine in one or more embodiments in office or example in an appropriate manner.Additionally, when not conflicting, the feature of the different embodiments described in this specification or example and different embodiment or example can be carried out combining and combining by those skilled in the art.
Although above it has been shown and described that embodiments of the invention, it is understandable that, above-described embodiment is illustrative of, it is impossible to be interpreted as limitation of the present invention, and above-described embodiment can be changed, revises, replace and modification by those of ordinary skill in the art within the scope of the invention.

Claims (10)

1. the visible light communication method towards brightness adjustment control, it is characterised in that comprise the following steps:
Treat transmitted bit to be modulated obtaining positive signal frame and minus polarity signal frame；
Proportion and the signal frame amplification factor of described positive signal frame and minus polarity signal frame is determined according to required light modulation degree；
Described positive signal frame and minus polarity signal frame are multiplied by described signal frame amplification factor, and carry out mixing to obtain mixed signal frame according to described proportion；And
By the minus polarity signal frame in described mixed signal frame plus direct current biasing, to obtain signal frame to be sent, after described signal frame to be sent is carried out digital to analog conversion, frequency conversion, filtering, control visible ray drive electric current, and send after obtaining visible light communication signal.
2. the visible light communication method towards brightness adjustment control as claimed in claim 1, it is characterised in that described positive signal is ACO-OFDM signal frame, PAM-DMT signal frame and the one in HACO-OFDM signal frame；Described minus polarity signal frame carries out positive portion zero setting by the bipolar signal before described ACO-OFDM signal frame or described PAM-DMT signal frame or the described asymmetric amplitude limit of HACO-OFDM signal frame and retains described bipolar signal negative fraction and obtain.
3. the visible light communication method towards brightness adjustment control as claimed in claim 1, it is characterised in that the maximum current that the value of described direct current biasing is interval less than or equal to visible-light linear.
4. the visible light communication method towards brightness adjustment control as claimed in claim 1, it is characterised in that
If described required light modulation degree is less than first threshold, only uses described positive signal frame, and reach described required light modulation degree by adjusting described signal amplification factor；
If described required light modulation degree is more than Second Threshold, only uses described minus polarity signal frame, and reach described required light modulation degree by adjusting described signal amplification factor；And
If described required light modulation degree is between described first threshold and Second Threshold, fixing described signal amplification factor, regulate the ratio of described positive signal and minus polarity signal, so that described positive signal frame and the weighted mean of minus polarity signal frame are equal to described required light modulation degree.
5. the visible light communication method towards brightness adjustment control as claimed in claim 4, it is characterized in that, described first threshold and described Second Threshold are fixed really, reach default value for making time-domain signal cut top ratio, or it is maximum with the ratio cutting top distortion power and noise power sum to make signal power.
6. the visible light communication device towards brightness adjustment control, it is characterised in that including:
Signal generation module, is used for treating transmitted bit and is modulated obtaining positive signal frame and minus polarity signal frame；
Parameter generation module, for determining proportion and the signal frame amplification factor of described positive signal frame and minus polarity signal frame according to required light modulation degree；
Signal fused module, for described positive signal frame and minus polarity signal frame are multiplied by described signal frame amplification factor, and carries out mixing to obtain mixed signal frame according to described proportion；And
Signal transmitting module, for the minus polarity signal frame in described mixed signal frame is added direct current biasing, to obtain signal frame to be sent, drive electric current described signal frame to be sent carries out controlling after digital to analog conversion, frequency conversion, filtering visible ray, and send after obtaining visible light communication signal.
7. the visible light communication device towards brightness adjustment control as claimed in claim 6, it is characterised in that described positive signal is ACO-OFDM signal frame, PAM-DMT signal frame and the one in HACO-OFDM signal frame；Described minus polarity signal frame carries out positive portion zero setting by the bipolar signal before described ACO-OFDM signal frame or described PAM-DMT signal frame or the described asymmetric amplitude limit of HACO-OFDM signal frame and retains described bipolar signal negative fraction and obtain.
8. the visible light communication device towards brightness adjustment control as claimed in claim 6, it is characterised in that the maximum current that the value of described direct current biasing is interval less than or equal to visible-light linear.
9. the visible light communication device towards brightness adjustment control as claimed in claim 6, it is characterised in that
When described required light modulation degree is less than first threshold, only uses described positive signal frame, and reach described required light modulation degree by adjusting described signal amplification factor；
When described required light modulation degree is more than Second Threshold, only uses described minus polarity signal frame, and reach described required light modulation degree by adjusting described signal amplification factor；And
When described light modulation degree is between described first threshold and Second Threshold, fixing described signal amplification factor, regulate the ratio of described positive signal and minus polarity signal, so that described positive signal frame and the weighted mean of minus polarity signal frame are equal to described required light modulation degree.
10. the visible light communication device towards brightness adjustment control as claimed in claim 9, it is characterized in that, described first threshold and described Second Threshold are fixed really, reach default value for making time-domain signal cut top ratio, or it is maximum with the ratio cutting top distortion power and noise power sum to make signal power.
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